docs(amiga): complete AmigaOS 3.1/3.2 developer reference — 172 files across 17 sections

Comprehensive technical documentation covering:
- Hardware: OCS/ECS/AGA custom chip registers, Copper & Blitter deep dives
- Boot sequence: cold boot through startup-sequence
- Binary format: HUNK executable spec, relocation, debug info
- Linking & ABI: .fd files, LVO tables, register calling conventions
- Exec kernel: tasks, interrupts, memory, signals, semaphores
- AmigaDOS: file I/O, FFS/OFS layout, CLI/Shell scripting
- Graphics: planar bitmaps, Copper programming, HAM/EHB modes
- Intuition: screens, windows, IDCMP, BOOPSI
- Devices: trackdisk, SCSI, serial, timer, audio, keyboard
- Libraries: utility, expansion, IFFParse, locale, ARexx
- Networking: bsdsocket API, SANA-II, TCP/IP stack comparison
- Toolchain: GCC, vasm/vlink, SAS/C, NDK, debugging
- Reverse engineering: IDA/Ghidra setup, compiler fingerprints, case studies
- CPU & MMU: 68040/060 emulation libs, PMMU, cache management
- Driver development: SANA-II, Picasso96/RTG, AHI audio

All files include breadcrumb navigation. No local paths or proprietary content.

08_graphics/blitter.md

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+[← Home](../README.md) · [Graphics](README.md)
+
+# Blitter — DMA Engine, Minterms, BltBitMap
+
+## Overview
+
+The **Blitter** is a DMA engine in the custom chips that performs bulk memory operations: block copies, line drawing, area fills, and arbitrary boolean combinations of up to three source bitmaps. It operates independently of the CPU, freeing the 68k for other work.
+
+---
+
+## Channels
+
+The blitter has four DMA channels:
+
+| Channel | Name | Direction | Description |
+|---|---|---|---|
+| A | Source A | Read | First source bitmap |
+| B | Source B | Read | Second source (often mask/pattern) |
+| C | Source C | Read | Third source (typically destination for read-modify-write) |
+| D | Destination | Write | Output |
+
+Each channel has: pointer register, modulo register, shift register (A/B only), and first/last word masks (A only).
+
+---
+
+## Minterm Logic
+
+The blitter combines A, B, C inputs using an 8-bit **minterm** value. Each bit selects whether the output is 1 for a specific combination:
+
+| Bit | A | B | C | Common Use |
+|---|---|---|---|---|
+| 7 | 1 | 1 | 1 | — |
+| 6 | 1 | 1 | 0 | — |
+| 5 | 1 | 0 | 1 | — |
+| 4 | 1 | 0 | 0 | — |
+| 3 | 0 | 1 | 1 | — |
+| 2 | 0 | 1 | 0 | — |
+| 1 | 0 | 0 | 1 | — |
+| 0 | 0 | 0 | 0 | — |
+
+Common minterm values:
+
+| Minterm | Hex | Operation |
+|---|---|---|
+| `$F0` | `A` | Copy A to D (straight copy) |
+| `$CA` | `AB + ~AC` | Cookie-cut: A=mask, B=source, C=background |
+| `$3C` | `A XOR C` | XOR blit (sprite toggle) |
+| `$0F` | `NOT A` | Invert source |
+| `$00` | `0` | Clear destination |
+| `$FF` | `1` | Fill destination with 1s |
+
+---
+
+## Register Map
+
+| Address | Name | Description |
+|---|---|---|
+| `$DFF040` | `BLTCON0` | Control: use-channels + minterm + shift-A |
+| `$DFF042` | `BLTCON1` | Control: direction, fill mode, line mode |
+| `$DFF044` | `BLTAFWM` | First word mask for channel A |
+| `$DFF046` | `BLTALWM` | Last word mask for channel A |
+| `$DFF048` | `BLTCPT` | Channel C pointer (high word) |
+| `$DFF04A` | `BLTCPT` | Channel C pointer (low word) |
+| `$DFF04C` | `BLTBPT` | Channel B pointer |
+| `$DFF050` | `BLTAPT` | Channel A pointer |
+| `$DFF054` | `BLTDPT` | Channel D pointer (destination) |
+| `$DFF058` | `BLTSIZE` | Size and start: `(height << 6) | width_words` |
+| `$DFF064` | `BLTCMOD` | Channel C modulo |
+| `$DFF062` | `BLTBMOD` | Channel B modulo |
+| `$DFF060` | `BLTAMOD` | Channel A modulo |
+| `$DFF066` | `BLTDMOD` | Channel D modulo |
+
+---
+
+## OS-Level Blitter Functions
+
+```c
+/* graphics.library */
+
+/* Copy rectangular region between bitmaps: */
+LONG BltBitMap(
+    struct BitMap *srcBM, WORD srcX, WORD srcY,
+    struct BitMap *dstBM, WORD dstX, WORD dstY,
+    WORD sizeX, WORD sizeY,
+    UBYTE minterm,             /* usually $C0 = copy */
+    UBYTE mask,                /* plane mask */
+    APTR tempA                 /* temp buffer or NULL */
+);
+
+/* Blit into RastPort (clips to layer): */
+void BltBitMapRastPort(struct BitMap *src, WORD srcX, WORD srcY,
+                       struct RastPort *rp, WORD dstX, WORD dstY,
+                       WORD sizeX, WORD sizeY, UBYTE minterm);
+
+/* Wait for blitter completion: */
+void WaitBlit(void);   /* must call before freeing blit buffers */
+
+/* Gain exclusive blitter access: */
+void OwnBlitter(void);
+void DisownBlitter(void);
+```
+
+---
+
+## References
+
+- HRM: *Amiga Hardware Reference Manual* — Blitter chapter
+- NDK39: `hardware/blit.h`, `graphics/gfx.h`
+- ADCD 2.1: `BltBitMap`, `BltBitMapRastPort`, `OwnBlitter`